Systems and methods for power savings in HFC amplifiers

ABSTRACT

Methods and systems that reduce power usage in a CATV network. Power usage may be reduced by temporally adjusting the power output of amplifiers in the network. The power output of one or more amplifiers in the network are preferably adjusted based on patterns of temporal usage of the network.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/709,632 filed Dec. 10, 2019, now U.S. Pat. No. 10,785,048issued Sep. 22, 2020, which is a continuation of U.S. patent applicationSer. No. 15/845,121 filed Dec. 18, 2107, now U.S. Pat. No. 10,523,459issued Dec. 31, 2019, the contents of which are incorporated herein byreference in their entirety.

BACKGROUND

A cable television (CATV) system is capable of providing a variety ofmedia content, such as video, data, voice, or high-speed Internetservices to subscribers. The CATV provider typically delivers the mediacontent from a head end to its subscriber's client devices over atransmission network such as a coaxial network, a fiber optic network,or a hybrid fiber/coax (HFC) network. Requirements for data throughput(or bandwidth) in these CATV networks are growing exponentially ascustomers demand more content, data services, etc. Though improvementsin encoding efficiencies and transport protocols have thus far allowedcable operators to keep pace with subscriber and competitive demands, itis important to continue the analysis of the various network elementsthat can enhance or inhibit the overall performance of next-generationcable networks.

One network element that constrains performance of cable networks ispower consumption, which rises dramatically as demand for more servicesand higher quality service rises. Recent analyses have shown that powerconsumption between the head end and the end user accounts for the vastmajority of power that MSOs consume. Specifically, as much as 83% ofcable's overall energy consumption is consumed by hubs, head ends, andactive power elements along the HFC network.

Therefore, it would be desirable to reduce power usage in a HFC networkwithout compromising output signal power in relation to noise.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating embodiments described below, there areshown in the drawings example constructions of the embodiments; however,the embodiments are not limited to the specific methods andinstrumentalities disclosed. In the drawings:

FIG. 1 shows an exemplary distribution profile of hourly usage in a CATVsystem.

FIG. 2 shows different “virtual” RF level outputs needed for respectiveforward frequencies used to deliver CATV content.

FIG. 3 shows an exemplary method for reducing power levels in anamplifier/node of a CATV network.

FIG. 4 shows an exemplary technique for modulating the power in a nodeamong more than two levels.

FIG. 5 shows an exemplary architecture to implement the method shown inFIG. 3.

FIG. 6 shows an exemplary amplifier/node in the architecture of FIG. 5.

It should be understood that, while the accompanying figures illustrateembodiments that include the portions of the disclosure claimed, andexplain various principles and advantages of those embodiments, thedetails displayed are not necessary to understand the illustratedembodiments, as the details depicted in the figures would be readilyapparent to those of ordinary skill in the art having the benefit of thepresent disclosure.

DETAILED DESCRIPTION

The present disclosure describes systems and methods that reduce powerconsumption in a CATV network.

As noted earlier, a large proportion of the total power usage by a CATVprovider is consumed along the transmission path between a head end anda customer, and particularly by active elements such as amplifiers. Mostof the radio frequency (RF) amplifiers within the cable televisionnetwork operate in what is referred to as a “class A” mode of operation,which provides a very high fidelity signal, often quantified in terms ofsignal-to-noise and signal-to-2nd, 3rd, 4th, 5th . . . harmonicdistortion products. However, the power consumption costs for the classA mode of operation is on the order of 100 times higher than thecomposite power of an RF output signal. This higher power consumptionresults from the need to accommodate significant and frequent ‘peak toaverage’ deviations from the effective signal power, which may includesetting the output RF rms amplitude of the amplifier at no more thanroughly 25% of the output rail-to-rail range of either voltage orcurrent, depending on the implementation. The higher demand for powerconsumption drives up the cost of cable network products that require RFgain blocs (e.g., head end optical transmitters and receivers,fiber-optic nodes, RF distribution amplifiers). Thus, it is desirable toreduce the power dissipation in a CATV network.

One might think that, if an amplifier is not transmitting power on achannel, its power output is automatically reduced. This does not occurwith Class A amplifiers, however, which dissipate a virtually constantpower independent of the number of channels it transmits because theamplifier is biased with a signal intended to correspond to the peakamplitude of the signals it amplifies. Thus, to reduce the powerconsumption in a class A amplifier, a method such as reducing the biascurrent and/or operating voltage is required, which adjusts the maximumRF output power capability of the amplifier for the desired RF qualityusing a metric such as MER.

To this end, a number of techniques have been proposed to modify thebias point of CATV amplifiers, or the signals they transmit so as toconserve power. Such techniques include Envelope Tracking (ET) andDigital Pre-Distortion (DPD) techniques, which show promise forsignificant improvements in energy efficiency. However, these techniquesrequire a very tight high speed, closed-loop system with sub-microsecondresponse times. While this might be achievable for a Distributed AccessArchitecture (DAA) with a digital link such as Remote PHY or RemoteMACPHY, where the Digital Analog Converter (DAC) is physically adjacentthe amplifier, it is not suitable for Centralized Access Architectures(CAA) where the DAC may be separated from the amplifiers by longdistances, and the amplifier housing receives a broadband RF signal.

Referring to FIG. 1, which shows an exemplary daily broadband usagepatterns, usage of a CATV network varies considerably over a day,typically in predictable, repetitive patterns. In the example shown,downstream capacity peak is more than four times that of the overnightlow, and if the 24-hour period is segmented into quartiles, roughly 10hours is spent in the 25-50% band; 10 hours in the 50-75% band and 4hours in the 75-100% band. Thus, the present inventors realized that,even where a node or amplifier is capable of a high frequency, highpower of operation, e.g. 1.2 GHz, that node may well be able to operateat a lower power of operation during predictable intervals of a day.Similar circumstances may arise, for example, when a system with MoCAfilters deployed at a customer's point of entry prevents the use ofhigher DOCSIS 3.1 frequencies (e.g. 1002-1218 MHz). Such modulations mayresult in significant power savings. FIG. 2 shows the “virtual” RF leveloutput needed for different forward frequencies. As can be seen, a 1218MHz DOCSIS 3.1 system requires significantly higher output levels than atraditional 750 MHz system. Thus, by virtually reducing the capacityprovided during intervals or conditions where the higher capacity is notnecessary may achieve significant reductions in power consumption.

Accordingly, a novel technique of reducing power consumption in a nodemay reduce power during non-peak bandwidth usage, e.g. the 20-hourwindow outside the peak period. This may be accomplished using any oneor more of several techniques. First, for example, during periods ofrelatively low activity, traffic may be consolidated onto fewerchannels, and unused DOCSIS/QAM channels may be turned off. In someembodiments, channels at higher frequencies which require more power dueto higher coax losses are turned off in favor of channels at lowerfrequencies. Alternatively, the order of modulation on a given channelmay be reduced, which allows output power to be reduced whilemaintaining the same SNR levels. Thus, for example, a QAM/DOCSIS 3.0modulation may be changed from 256-QAM to 64-QAM to achieve a 6-7 dBreduction in required output power at the same SNR with 75% of thecapacity. As another example, a DOCSIS 3.1 modulation may be changedfrom 4096-QAM to 256-QAM to achieve a 12-14 dB reduction in requiredoutput power at the same SNR with 66.6% of the capacity. Note that someQAM channels such as digital broadcast may need to remain at a fixedmodulation while other QAM channels such as DOCSIS 3.0 with varyingcapacity may be adapted to different modulation orders.

Referring to FIG. 3, one exemplary method 10 to modulate the powerconsumption in a CATV system would begin at step 12 where informationwould be determined regarding data usage patterns. In step 14, the usagepatterns are used to determine a time-varying signal that modulates oneor more characteristics of the CATV system at step 16. For example, thetime-varying signal may be used by a head end to reduce the number ofchannels sent to downstream nodes/amplifiers or reduce the order ofmodulation of the channels. Simultaneously, the nodes/amplifiers mayadjust output power and/or bias level to correspond to the reducednumber of channels or reduced order of modulation.

Because such patterns are usually predictable, daily patterns may bepredetermined and used repetitively over sequential days. For example, ahead end could send signals to a node/amplifier at predetermined timesof the day. Alternatively, data usage may be measured over a shorterinterval, even instantaneously. For example, detection circuitry in botha head end and a housing of an amplifier/node may each independentlysense instantaneous RF bandwidth, or other relevant metrics indicativethe amount of bandwidth that is actually being used. The headend couldreduce the number of channels and/or modulation orders used and theamplifier/node could autonomously adjust its output power for the new RFbandwidth.

Those of ordinary skill in the art will appreciate that the disclosedmethod may be tailored to provide any number of levels or tiers of powerconsumption. For example, during peak times, the method may provideoperation as a full 1218 MHz system with full bandwidth capacitycapabilities at maximum modulation orders. During shoulder times, thesystem could operate as a 1002 MHz system or with reduced modulationorders, and during off-peak times the system could operates as a 750 MHzsystem with reduced modulation orders. Referring to FIG. 4, for example,in an embodiment 50 where a head end sends a downstream signal based ona predetermined pattern of usage during a day, different signals orcodes may effectuate different power levels. Thus, for instance a codeof “011” may correspond to normal “full” operation of the system, e.g.1218 MHz. at maximum modulation orders. A code of “010” may signal thattraffic is to be consolidated to eliminate channels associated with thehighest frequencies, so as to attain a 1002 MHz system. A code of “001”or “000” can reduce the upper frequency even further to 870 or 750 MHzrespectively. Alternatively, a code of “111” may signal that the QAMmodulation orders of the channels are reduced, at all of the availablechannels, to reduce both capacity and power consumption in a 1218 MHzsystem. A code of “110”, “101” or “100” may signal that traffic is to beconsolidated to eliminate channels associated with the highestfrequencies and that the remaining channels will operate at a lower QAMlevel to attain a system of 1002, 870 or 750 MHz respectively. Furtherfine-tuning can be achieved simply by having finer gradations ofconsolidation and/or QAM levels.

The disclosed method provides flexibility in several important respects.First, changes in usage are very slow compared to network speeds, hencethe amplifier/node output power might only need to be modulated ahandful of times per day. Therefore, implementation of the method merelyneeds a very low bandwidth link, which should translate into lower costsand power. Second, disclosed method does not require two-waycommunication. Because of the slow time varying nature of updates, thepower information can be repeatedly broadcast. Those of ordinary skillin the art will appreciate, however, that a two-way communication linkmight be beneficial for implementing energy management protocols such asSCTE EMS APSIS, but as just noted, bidirectional communication is notrequired.

Furthermore, implementation of a power control system to implement thedisclosed system can also operate in complete isolation. As alreadynoted for example, detection circuitry in both a head end and a housingof an amplifier/node may independently sense usage and adjustperformance to implement a lower power output.

FIG. 5 shows an exemplary cable television (CATV) system 100 operable todeliver high-definition digital entertainment and telecommunicationssuch as video, voice, and high-speed Internet services using thedisclosed method. Generally speaking, the CATV system 100 refers to theoperational (e.g., geographical) footprint of an entertainment and/orinformation services franchise that provides entertainment and/orinformation services to a subscriber base spanning one or more towns, aregion, or a portion thereof. Particular entertainment and/orinformation services offered by the franchise (e.g., entertainmentchannel lineup, data packages, etc.) may differ from system to system.Some large cable companies operate several cable communication systems(e.g., in some cases up to hundreds of systems), and are known generallyas Multiple System Operators (MSOs).

The cable network can take the form of an all-coax, all-fiber, or hybridfiber/coax (HFC) network, e.g., fiber to the last amplifier (FTTLA). Forpurposes of illustration only, FIG. 1 depicts a hybrid fiber-coaxial(HFC) network. An HFC network is a broadband network that combinesoptical fiber and coaxial cable, strategically placing fiber nodes toprovide services to a plurality of homes. It should be understood thatthe systems and methods disclosed in the present application may beemployed in various networks and the HFC network is merely shown as anon-limiting example.

The network shown in FIG. 5 is an HFC broadband network that combinesthe use of optical fiber and coaxial connections. The network includes ahead end 102 that receives analog video signals and digital bit streamsrepresenting different services (e.g., video, voice, and Internet) fromvarious digital information sources. For example, the head end 102 mayreceive content from one or more video on demand (VOD) servers, IPTVbroadcast video servers, Internet video sources, or other suitablesources for providing IP content.

An IP network 108 may include a web server 110 and a data source 112.The web server 110 is a streaming server that uses the IP protocol todeliver video-on-demand, audio-on-demand, and pay-per view streams tothe IP network 108. The IP data source 112 may be connected to aregional area or backbone network (not shown) that transmits IP content.For example, the regional area network can be or include the Internet oran IP-based network, a computer network, a web-based network or othersuitable wired or wireless network or network system.

At the head end 102, the various services are encoded, modulated andup-converted onto RF carriers, combined onto a single electrical signaland inserted into a broadband optical transmitter. A fiber optic networkextends from the cable operator's master/regional head end 102 to aplurality of fiber optic nodes 104. The head end 102 may contain anoptical transmitter or transceiver to provide optical communicationsthrough optical fibers 103. Regional head ends and/or neighborhood hubsites may also exist between the head end and one or more nodes. Thefiber optic portion of the example HFC network 100 extends from the headend 102 to the regional head end/hub and/or to a plurality of nodes 104.The optical transmitter converts the electrical signal to a downstreamoptically modulated signal that is sent to the nodes. In turn, theoptical nodes convert inbound signals to RF energy and return RF signalsto optical signals along a return path. In the specification, thedrawings, and the claims, the terms “forward path” and “downstream” maybe interchangeably used to refer to a path from a head end to a node, anode to a subscriber, or a head end to a subscriber. Conversely, theterms “return path”, “reverse path” and “upstream” may beinterchangeably used to refer to a path from a subscriber to a node, anode to a head end, or a subscriber to a head end. Also, in thespecification, in the drawings, and the claims a node may be any digitalhub between a head end and a customer home that transports localrequests over the CATV network. Forward path optical communications overthe optical fiber may be converted at the nodes to Radio Frequency (RF)communications for transmission over the coaxial cable to thesubscribers. Conversely, return path RF communications from thesubscribers are provided over coaxial cables and are typically convertedat a node to optical signals for transmission over the optical fiber tothe head end. Each node 104 may contain a return path transmitter thatis able to relay communications upstream from a subscriber device 106 tothe head end 102.

Each node 104 serves a service group comprising one or more customerlocations. By way of example, a single node 104 may be connected tothousands of cable modems or other subscriber devices 106. In anexample, a fiber node may serve between one and two thousand or morecustomer locations. In an HFC network, the fiber optic node 104 may beconnected to a plurality of subscriber devices 106 via coaxial cablecascade 111, though those of ordinary skill in the art will appreciatethat the coaxial cascade may comprise a combination of fiber optic cableand coaxial cable. In some implementations, each node 104 may include abroadband optical receiver to convert the downstream optically modulatedsignal received from the head end or a hub to an electrical signalprovided to the subscribers' devices 106 through the coaxial cascade111. Signals may pass from the node 104 to the subscriber devices 106via the RF cascade 111, which may be comprised of multiple amplifiersand active or passive devices including cabling, taps, splitters, andin-line equalizers. It should be understood that the amplifiers in theRF cascade 111 may be bidirectional, and may be cascaded such that anamplifier may not only feed an amplifier further along in the cascadebut may also feed a large number of subscribers. The tap is thecustomer's drop interface to the coaxial system. Taps are designed invarious values to allow amplitude consistency along the distributionsystem.

The subscriber devices 106 may reside at a customer location, such as ahome of a cable subscriber, and are connected to the cable modemtermination system (CMTS) 120 or comparable component located in a headend. A client device 106 may be a modem, e.g., cable modem, MTA (mediaterminal adaptor), set top box, terminal device, television equippedwith set top box, Data Over Cable Service Interface Specification(DOCSIS) terminal device, customer premises equipment (CPE), router, orsimilar electronic client, end, or terminal devices of subscribers. Forexample, cable modems and IP set top boxes may support data connectionto the Internet and other computer networks via the cable network, andthe cable network provides bi-directional communication systems in whichdata can be sent downstream from the head end to a subscriber andupstream from a subscriber to the head end.

The techniques disclosed herein may be applied to systems compliant withDOCSIS. The cable industry developed the international Data Over CableSystem Interface Specification (DOCSIS®) standard or protocol to enablethe delivery of IP data packets over cable systems. In general, DOCSISdefines the communications and operations support interface requirementsfor a data over cable system. For example, DOCIS defines the interfacerequirements for cable modems involved in high-speed data distributionover cable television system networks. However, it should be understoodthat the techniques disclosed herein may apply to any system for digitalservices transmission, such as digital video or Ethernet PON over Coax(EPoc). Examples herein referring to DOCSIS are illustrative andrepresentative of the application of the techniques to a broad range ofservices carried over coax.

References are made in the present disclosure to a Cable ModemTermination System (CMTS) in the head end 102. In general, the CMTS is acomponent located at the head end or hub site of the network thatexchanges signals between the head end and client devices within thecable network infrastructure. In an example DOCSIS arrangement, forexample, the CMTS and the cable modem may be the endpoints of the DOCSISprotocol, with the hybrid fiber coax (HFC) cable plant transmittinginformation between these endpoints. It will be appreciated thatarchitecture 100 includes one CMTS for illustrative purposes only, as itis in fact customary that multiple CMTSs and their Cable Modems aremanaged through the management network.

The CMTS 120 hosts downstream and upstream ports and contains numerousreceivers, each receiver handling communications between hundreds of enduser network elements connected to the broadband network. For example,each CMTS 120 may be connected to several modems of many subscribers,e.g., a single CMTS may be connected to hundreds of modems that varywidely in communication characteristics. In many instances severalnodes, such as fiber optic nodes 104, may serve a particular area of atown or city. DOCSIS enables IP packets to pass between devices oneither side of the link between the CMTS and the cable modem.

It should be understood that the CMTS is a non-limiting example of acomponent in the cable network that may be used to exchange signalsbetween the head end and subscriber devices 106 within the cable networkinfrastructure. For example, other non-limiting examples include aModular CMTS (M-CMTS™) architecture or a Converged Cable Access Platform(CCAP).

An EdgeQAM (EQAM) 122 or EQAM modulator may be in the head end or hubdevice for receiving packets of digital content, such as video or data,re-packetizing the digital content into an MPEG transport stream, anddigitally modulating the digital transport stream onto a downstream RFcarrier using Quadrature Amplitude Modulation (QAM). EdgeQAMs may beused for both digital broadcast, and DOCSIS downstream transmission. InCMTS or M-CMTS implementations, data and video QAMs may be implementedon separately managed and controlled platforms. In CCAP implementations,the CMTS and edge QAM functionality may be combined in one hardwaresolution, thereby combining data and video delivery.

Orthogonal frequency-division multiplexing (OFDM) may utilize smallersubcarriers (compared to QAM carriers). For example, while aconventional DOCSIS QAM carrier is 6 MHz wide, the CATV system mayemploy orthogonal frequency division multiplexing (OFDM) technology withOFDM carriers that are approximately 25 kHz to 50 kHz wide. Thus, wherepreviously 100 QAM carriers were used, thousands of OFDM subcarriers maybe used. OFDM technology may be suitable for noisy signal conditions andmay enable use of more of the available spectrum without reducing thequality of server. In example implementations, a cable network may usethe QAM modulation for downstream speeds and boost upstream speeds usingOFDM.

FIG. 6 shows an exemplary node 104 of the HFC network 100. The node 104may have an amplifier 130 that receives a bias signal 132 and amplifiesan downstream signal 103 from a head end, which may include an RFsignal, a digital signal converted to an RF signal by a DAC (not shown)in the node 104, or a combination of RF and digital signals (e.g. an RFsignal for downstream content and a digital communication signalcontaining control information, Internet content, etc.). Preferably, thenode 104 includes a controller 134 used to modulate the input signal tothe amplifier 130, the bias level 132 of the amplifier, or both,according to one or more of the methods previously discussed. Forexample, the controller 134 may receive a control code from the head endinside the signal 134 and modulate the bias and/or operating voltages ofthe amplifier 130 accordingly. The control code from the head end 102may, in some embodiments, be included in an out-of-band (OOB) links usedby STBs. Alternatively, since the bandwidth requirements of thedisclosed techniques are so low, some embodiments could leverage DOCSIS3.1 technology to provide a control signal since only one carrier, or asmall number of subcarriers, would be needed to convey the requiredinformation. The DOCSIS 3.1 specification could be augmented to passthis control information down the existing PHY Link Control (PLC)channel. Still other such embodiments could embed the power controlinformation into DOCSIS 3.1 pilots, e.g. embedded inside the QPSKpatterns within a pilot or other unique pilot patterns. Alternatively, aproprietary link could be created using a single sub-carrier.

Still another embodiment could place a DOCSIS cable modem chip in thehousing of the node 104, i.e. controller 134 could be a DOCSIS cablemodem chip. With such a chip included, the HFC amplifier/node can becomea managed device and utilize protocols such as SCTE EMS APSIS.

In some embodiments, if the node 104 does not receive a signal over apredetermined interval, then the power control system defaults to fullbandwidth/power until communication is re-established. In this mode, thecontroller 134 may still be able to detect the presence or absence ofcarriers in the upper frequency channels, and set the upper frequencybound of the node with an appropriate amplifier bias level.

Preferably, the amplifier 130 in the node 104 would operate at aconstant efficiency for the same RF quality. Thus, for every dB of RFoutput power reduction, the RF amplifier bias and/or voltage would beadjusted and save 1 dB of power consumption. Alternatively, the gain ofthe amplifier may be constant regardless of the change in RF amplifierbias and/or voltage. Preferably, both of these implementations arecharacterized in advance, and employ a look-up table to control settingsand/or use feedback to assure proper operation.

In one or more examples, the functions disclosed herein may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted as one or more instructions or code on a computer-readablemedium and executed by a hardware-based processing unit.Computer-readable media may include computer-readable storage media,which corresponds to a tangible medium such as data storage media, orcommunication media including any medium that facilitates transfer of acomputer program from one place to another, e.g., according to acommunication protocol. In this manner, computer-readable mediagenerally may correspond to (1) tangible computer-readable storage mediawhich is non-transitory or (2) a communication medium such as a signalor carrier wave. Data storage media may be any available media that canbe accessed by one or more computers or one or more processors toretrieve instructions, code and/or data structures for implementation ofthe techniques described in this disclosure. A computer program productmay include a computer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. “Disk” and“disc” as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses. Various components, modules, or units aredescribed in this disclosure to emphasize functional aspects ofcomponents configured to perform the disclosed techniques, but do notnecessarily require realization by different hardware units. Rather, asdescribed above, various units may be combined in a codec hardware unitor provided by a collection of interoperative hardware units, includingone or more processors as described above, in conjunction with suitablesoftware and/or firmware.

The invention claimed is:
 1. A method for adjusting power usage of aCable TV (CATV) network, the method comprising selectively changingorder of modulation of at least one downstream Quadrature AmplitudeModulation (QAM) channel in the CATV network, and sending a signal todownstream device, the signal used by the downstream device to reducepower based on the changed order of modulation.
 2. The method of claim 1where the step of changing the order of modulation of at least onedownstream channel changes available capacity of the CATV network. 3.The method of claim 2 including the step of consolidating channels andreducing the upper frequency bound of downstream content amplified bythe amplifier.
 4. The method of claim 2 including the step of temporallymodulating power of an amplifier in the downstream device.
 5. The methodof claim 1 where the signal is based upon a temporal pattern of usage ofthe CATV network.
 6. The method of claim 5 where the temporal pattern ofusage is determined at a head end and the head end sends the signal. 7.The method of claim 5 where the signal is used to modulate the biaspoint of an amplifier in the downstream device.
 8. The method of claim 7where a head end independently determines the temporal pattern of usageand modulates the signal to the downstream device to communicate a modeof operation.
 9. A device in a Cable TV (CATV) network downstream from ahead end, the device comprising: (a) an input for receiving a firstdownstream signal and a second downstream signal, the first downstreamchannel being a Quadrature Amplitude Modulation (QAM) channel, thesecond downstream signal varying based upon a selectively changing orderof modulation of the first downstream signal; (b) an amplifier foramplifying the first downstream signal; and (c) a controller capable ofadjusting power consumed by the device by using the second downstreamsignal.
 10. The device of claim 9 including a Data over Cable ServiceInterface Specification (DOCSIS) cable modem chip.
 11. The device ofclaim 9 where the second signal varies based on a temporally varyingmagnitude of usage of the CATV system.
 12. The device of claim 11 wherethe second signal is received in an Out-of-Band (00B) channel.
 13. Thedevice of claim 11 where the second signal is received in a DOCSIS 3.1PHY Link Control (PLC) channel.
 14. The device of claim 11 where thesecond signal is received in a DOCSIS 3.1 subcarrier.
 15. The devicenode of claim 11 where the second signal is received in a DOCSIS 3.1pilot.
 16. The device of claim 9 comprising a node.
 17. The device ofclaim 9 comprising an amplifier.
 18. The method of claim 1 where thedownstream device is a node.
 19. The method of claim 1 where thedownstream device is an amplifier.